Some aircraft engines have propellers with variable pitch, referred to as propeller blade (or beta) angle. In such engines, accurate control of the beta angle is important for proper engine operation. For example, control of the beta angle may allow the blade angle to be controlled according to the desired engine power set-point. Accurate measure of the blade angle also ensures that the propeller is not inadvertently commanded to transition into low or reverse beta angles, which would cause a potentially serious failure condition for the aircraft.
A propeller may form part of an assembly having numerous components. For example, a propeller may be mounted to a propeller shaft, which may itself be received in a gear box. Further components may also be present. Each component of the propeller assembly may be manufactured to a specific nominal size and tolerance. The dimensional configuration of a particular propeller assembly may be influenced by the tolerance stack-up. That is, the propeller position may depend on whether parts in the assembly are over or under their nominal sizes, and by how much. Accurate control of the propeller and propeller assembly may depend on the tolerance stack-up. Moreover, safe and efficient operation may require that the tolerance stack-up is within specification.